Resources: Materials for the Mission Assignment, such as balloons, pieces of wool cloth and access to a working water tap.
Handout: Questions related to the mission assignment and space for students to draw their diagrams.
Revise learning from previous units by reminding the students that electricity is a flow of charged particles and that electrical energy can be transformed into other forms of energy. Remind the students that all objects are made up of atoms - which consist of positively charged protons, negatively charged electrons, and neutral neutrons - and that the exchange of electrons between objects can result in the objects becoming charged.
Ask the students to describe what happens when you rub a balloon on your hair.
Review the presentation slides; in particular, focus on how electrons move from a conductor to an insulator.
Act It: Assign each student a label that says either positive or negative (distribute these roughly 50:50. On the word go, students who are positively charged should avoid going near other positively charged students (and vice-versa) and aim to pair up with someone of the opposite charge.
NB: When a positively charged student meets a negatively charged student, they can be considered a single neutral object.
Career Film: Take a tour around Rolls Royce SMR's Heritage Museum in Derby to find out about Sayalee Sawant's job. Sayalee works as a Systems Integration Engineer for Rolls Royce SMR.
Expert Film: This is Sayalee Sawant. Sayalee works as a Systems Integration Engineer for Rolls Royce SMR. Listen to Sayalee as she describes how objects become charged.
Ask the students to explain the phenomena they have seen in the Expert Film. They should keep their explanations about electron flow. They can use diagrams to help their explanation.
Support Task: Model electron flow around the classroom to recap circuits and then link this to modelling repulsive and attractive forces.
Challenge Task: Ask the students to predict what will happen if they place a balloon near a running stream of water after rubbing it against wool.
Then, ask the students to rub the balloon against the wool and then hold the balloon near a thin stream of running water (about 4mm thick). The water moves towards the balloon because water is a polarised molecule, meaning it has a positively charged side and a negatively charged side. The water molecules will rotate and spin when placed near a charged object. The students should then complete the questions on the handout.
Create a list of terms related to the lesson, and have students match each term with its definition. For example, "Electrons" could be matched with "negatively charged particles," and "Protons" could be matched with "positively charged particles."
Atom: the smallest portion into which an element can be divided and still retain its properties. Atoms are composed of a nucleus, containing protons and neutrons, surrounded by electrons.
Proton: a positively charged particle found inside the nucleus of an atom.
Neutron: a neutral particle found in the nucleus of an atom. Neutral particles contain no charge.
Electron: a negatively charged particle that orbits the nucleus of an atom.
Static Electricity: a build-up of an electric charge on an object.
All matter is made of atoms. The core, or nucleus, of an atom, consists of positively charged protons, surrounded by an outer “shell” of negatively charged electrons. Materials that have an equal amount of protons and electrons are considered to be balanced or neutral. However, when certain materials rub up against one another, the negatively charged electrons from one material can be picked up by the other material. This causes the material that loses electrons to be positively charged and the material that gains electrons to be negatively charged. The build-up of electrical charges on the surface of the material is called static electricity.
Static electricity can cause materials to attract or repel one another. Opposite charges attract, similar charges will repel and both types of charges will be attracted to a neutral material. In each of these activities, the balloon picked up electrons from the surface of the wool, causing the balloon to become negatively charged. The negatively charged balloon will now be attracted to materials that have an opposite charge, or to a neutral or balanced material (with no charge). This caused the cereal and the charged balloon to come towards each other. When the charged balloon touches the cereal, electrons will flow into the cereal, giving it a negative charge. This then causes them to repel each other.
A high accumulation of positive charges on the surface of one material and a high accumulation of negative charges on the surface of another material can cause an attraction between the charges so great that the electrons will jump the air gap between the objects. Once the electrons start to move across the gap, they heat up the dry air, causing a visible spark, or on a larger scale, lightning.